Silly resistor values

(e.g.,

Sure there is. It reduces P/N count, saving inventory problems and possibly a second (perhaps impossible) pass at the pick-n-place machine.

Different issues. Saving steps isn't the same as adding parts.

I rather liked IBM's.

(e.g.,

very

an

Thou shalt not use a machine that's close to being tapped out in terms of slots ;-)

But seriously, this problem was fixed with two measures:

a. All 100K resistors became 10%.

b. The contract mfg supplies stock and they've got no problem whatsoever with inventory because they make tons of other stuff. Otherwise they wouldn't have asked us.

No parts were added, they were changed in spec and ECO'd part numbers.

--
Regards, Joerg

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(e.g.,

very

an

be

In this economy, thou shalt use what thou has. Thou shalt not whine for new toys. ;-)

We don't use contract manufacturers. Inventory control isn't free. OTOH, if the owner was really interested in saving money, he'd insist that IT link the purchasing/inventory database and the engineering/production databases. As it is, I only have a hint at what _some_ parts cost, and I've caught purchasing buying parts for

4-5x what they should be paying.

Skipping a trim step adding a part number.

[...]

In larger companies that's linked. In the one where I took over a division it wasn't at that time but we made darn sure this was done, and soon.

Exactly that is one reason for using contract manufacturers. They never pay 4-5x of what they should be paying. More like 0.8-0.9x because with their qties they have so much more negotiating power.

Got to streamline that process. At Endosonics we "electronicized" the ECO process. No more walking a stack of papers to the next signing person. You could have an urgent ECO signed off in under 15 minutes. Anyhow, the first time I eased off resistor tolerances for a client it saved them 5c/unit. Doesn't sound like much. I billed 0.25 hours for my time for this task because that's all it took. Then they began to produce around 50k units/year, looks like this product could make it to the 20 year anniversary. For the cost savings to date you could buy a nicely equipped Cadillac (the owner did ...). Unfortunately this product has now survived the owner :-(

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Sorry, but even between different makers of metal film 1% resistors, there are differences in operation.

When you have 1mV ripple figure on a 4kV x-ray supply, changing a resistor maker can change that figure in a bad way usually. If what you sell is a sub 1mV PARD figure for that supply, and you have some lame contract maker build 100 of them for you, unless he knows how to keep to the BOM, you are going to get 100 different power supplies, and an unhappy customer.

Sure, my point was that it's usually worthwhile to spend the time to consider which parts can be substituted (or have their tolerances loosened) and which can't. Also that it's preferable to work with a CM who'll be sure to mention all the tricks *they* know that *might* allow you to reduce the costs of your design.

---Joel

If I were doing multiple M counts of a given build, *I* would economize the design, not the contract builder. They are nothing more than assemblers. My contract builds usually involve MY purchased parts. Were I to do a turnkey build, I would specify in the quote request, everything in the BOM that had to remain the same, right down to the maker, and everything which can be his turnkey part. He would not, however, get to reduce tolerances on a part. It is in no way up to the contract assembler house to make any design change decisions based on his guesses about the design or function of ANY given section of ANY given circuit design.

Bull. You can bet that the China builder is building the EXACT product Apple specs out, and Apple buys the entire facility, and stocks it with their part, and NOBODY is economizing the design of ANYTHING.

Did you honestly believe that Apple goes contract builder shopping in China, and picks someone that is building other things as well? I do not. I think they went over there and BOUGHT lock-stock-and-barrel everything. They OWN contract builders in China.

The mere fact that they are building there instead of here now, is enough margin gain alone. They do not need to piss around compromising their design to save one penny over a million capacitors. It is far cheaper to install the BOM, and save the admin fees of some dope spending a years salary to save $10k.

You can bet that with the volumes that Aplle sells, they are already getting all their electronic parts cheaper than you EVER did at ANY time in your ENTIRE LIFE. So they are ALREADY economized out the yin yang at the front end. There is no ass end economizing like that which you are familiar with ever needed.

The White Tornado

Andy Rooney would love it!

I said that it was *Apple* who's doing whatever they can to keep their costs down; no one here was suggesting a (good) CM would run off and start making changes to a design without getting sign-off from their customer.

I don't really know, but that is a very interesting question. I suppose they do have enough volume to do so if they wanted to.

The big savings are in the overall architecture, certainly -- I expect you've read Joerg's stories where he's been able to replace, e.g., an entire DSP (maybe $10?) with under a buck worth of discrete parts. That's significant. Heck, saving just ten cents on something you're building a million of per year is enough to fully pay a U.S. engineer's salary.

---Joel

[...]

Plus eliminated something like $150-200 worth of programmable digital delay lines per system. Oh, was that sales rep pissed.

1/4 hour of my billed time (to ease some resistor tolerances to 10%) bought the boss of a client savings worth a nice Cadillac over 15 production years. He took me to dinner in it, very nice ride :-)

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Regards, Joerg

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Well, we ALL already knew that. The thing is that you don't go letting your CM dictate such things to you.

The talk was never about the contract manufacturer dictating anything. They don't, or they lose the contract. What they did in my cases was suggesting something to be changed. That is most welcome feedback. Then it was up to my client who then left it up to me to figure out whether that is technically feasible. Sometimes resulting in rather remarkable cost savings.

Of course all this usually doesn't make much sense if you only produce

1000/year. But then you probably would not contract out anyhow.

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I am perfectly capable of doing a thorough "DFM" cycle. Cost reduction on parts came long before that.

Perhaps not with today's young engineers, but I come from a time when we knew more than any CM we ever contracted to build one of our designs.

That is certainly true where I am now, where every single part is verified, and no changes are even allowed. Tempest certs are tough, even for a simple USB device, for example.

All of our CMs build what we spec. Some of our kits have thousands of dollars worth of parts left over that never get used, and go past their usable service life for soldering before they could even get shoved back through the system. The admin to examine it alone would cost thousands.

If I could have all the expired popcorn that is around here, I could build several motherboards worth of assembly (like 50k + parts easily). All perfect parts, aside from the exp date. Hand solder is fine though. Primo parts. I wish I could have them all.

Oh man ...

Is that cost finally ending up with the taxpayer? If you had such left-overs in industry the responsible person would receive an "invitation" to the CFO's office, the door would be closed and it would get very loud in there.

This is one reason why I have steered companies away from the old kitting process pretty much everywhere I worked. It's wasteful.

So what happens with all that. It's chucked?

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I bit myself on this one once. I had drawn up a schematic for a module that we used in development - a dual-port RAM that acted like a ROM in- circuit.

Somebody told me that the assemblers could build from a schematic. Cool, I says, I don't have to do it! Unfortunately, I had used the convention of showing all the bypass caps on the bus, rather than at each chip with all those damn wires; when I got the board, there were the bypasses, in a nice neat row, right next to the power bus. It turned out not to be a problem; it took her about 10 minutes to add a half a dozen caps, so it was no big deal. I guess the moral is, be more specific. :-)

Cheers! Rich

At our company, stupidity like yours is what is wasteful. a few hundred, or even a few thousand left over discreet parts is no big deal when the assemblies are several tens of thousands of dollars as a finished product. A couple hundred bucks worth of attrition is not even worth tallying up.

Handling them in such a way as to re-introduce them into the MRP system would take long enough that many would be expired going in, and therefore unusable.

Unlike you, we cannot utilize parts that are past their solderability expiry dates, and ALL parts have them, whether you know it or not.

Ten years from now, when there is no chance that any component could be used to undermine the nation's security. Yes, even "dumb" components.